Reef Light

[ben1234]

i hear that if you want to keep corals that require high light intensity to use Metal Halide. What im wondering is if it acually has to be a metal halide bulb and fixture, or could i put in a high pressure sodium bulb and unit that emits 75 watts or a halogen unit putting off 96 watts. Why does it have to be Metal Halide? Why couldnt we just use a floodlight system or something like that? thanks guys

 

[ben1234]

Anyone know out there?

 

[macpegg]

Its all down to the spectrums each lights shoots out. I user T5`s and a triton and a marine light, as when u look at each they do look different in colour. But with floodlights... they would just burn the corals im sure. On the REEF: The sun is pretty dominant, so any house hold lights would be just no good. I can`t see places selling T5`s and halides for the price they do if they didn`t work.

I myself did just buy T5` lights without the casing. and did try to bodge.. but i failed miserably.. i can only guess that other people have tried. But now i have spare T5`s which i suppose is handy anyways.

 

[maestro]

Its all down to the spectrums each lights shoots out. I user T5`s and a triton and a marine light, as when u look at each they do look different in colour. But with floodlights... they would just burn the corals im sure. On the REEF: The sun is pretty dominant, so any house hold lights would be just no good. I can`t see places selling T5`s and halides for the price they do if they didn`t work.

I myself did just buy T5` lights without the casing. and did try to bodge.. but i failed miserably.. i can only guess that other people have tried. But now i have spare T5`s which i suppose is handy anyways.

To be honest im not an expert but I have read that some so called Metal Halide units are actually Mercury vapour ballasts and give out too much UV, there is a thread on another forum in which a guy used a so called cheap metal halide ballast and ended up losing most of his stock aswell as causing him severe burns

If you are in the UK marine lighting, http/www.marine-lighting.co.uk are very helpfull and over cheaper style safe ballasts

 

[bunjiweb]

Personally I would go for a large bank of T5s or Compact T5s over metal-halides any day, you can get a broad spectrum through using different bulbs and T5s don't "burn" corals like Metal Halides can, (think sunburn, but on corals).

Ben

 

[andywg]

High Pressure Sodium (HPS) is actually one of the best bulbs you can get, delivering far more lumens per watt than even Metal Halide. It also shines in pretty much the ideal colour temperature for coral growth. Sadly this colour temp also tends to make the water look like cat's wee.

You can buy better than standard HPS bulbs which will give a nicer look, and you can blue off the colour with some actinics.

Something I read on another forum on a dedicated lighting thread was a downside to T5s is they do not tend to dissipate in intensity as you go down the water column. So if it is too bright for a coral at the surface it will likely be too bright at the bottom. with MHs you can move the coral to a lower position where it will receive less bright. If you already have a suitable HPS I would definately use it.

HTH

Andy

 

[steelhealr]

It all comes down to color spectrum. To be honest, I'm not an expert on that bulb, but, I believe the spectrum of light is not the best for coral reefs. Metal halides mimic sunlight pretty closely. I believe the light you describe has more of a yellow spectrum. Don't take my word on it....research it..but, that was my impression. SH

 

[andywg]

The colour of MH depends on the bulb. They range from around 5-6,000 Kelvin (very close to the sun) all the way to 50,000K (very high into the blue end).

Yellow light is very close to the colour of the sun and will actually promote good coral growth (the "need" for actinics is basically a myth created by the industry. The corals grow in the sun which has a temperature of around 6,700 Kelvin). The down side is the lack of asthetics when using a bulb of this type, hence why most people get MH of around 10-14K giving better asthetics without losing too much of the coral growth.

The reason people generally use MH and not Sodium is because until recently you couldn't get the vast range of colours for HPS (only between 4 and 7K). If you want to see which bulbs mimic the sun best, look at the bulbs used by indoor botanists for "special" plants. They use HPS because of its great lumens per watt and thus cheaper running costs than MH as well as being a perfect colour.

Halogen lights are near uselss as they have no punch in the sort of light necessary for plant growth.

My best advice is an echo of SH though. Don't take my word for it, I could be wrong; research, research, research. The 3Rs of reefkeeping

HTH

Andy